Green tea cut obesity and a number of inflammatory biomarkers linked with poor health in a new study.
The benefits seen in the new study, published in the Journal of Nutritional Biochemistry, appear to stem from: 1) improved gut health, including more beneficial microbes in the intestines, and 2) less permeability in the intestinal wall -- a condition typically called "leaky gut" in people.
"This study provides evidence that green tea encourages the growth of good gut bacteria, and that leads to a series of benefits that significantly lower the risk of obesity," said Richard Bruno, the study's lead author and a professor of human nutrition at The Ohio State University.
Green tea has a rich history in Asian countries and has been increasingly embraced in the West, in part for its potential health benefits. Catechins, anti-inflammatory polyphenols found in green tea, have been linked to anti-cancer activity and lower risk of heart and liver disease.
In this animal study, mice fed a diet of 2 percent green tea extract fared far better than those that ate a diet without it, a finding that has prompted an upcoming study of green tea's potential benefits in people at high risk of diabetes and heart disease.
* For eight weeks, half of the animals ate a high-fat diet designed to lead to obesity and half were fed a regular diet.
** In each of those groups, half ate green tea extract mixed in with their food.
Then the researchers measured body and fat tissue weight, insulin resistance and other factors that included:
1) Gut permeability, or how 'leaky' the gut was 2) Endotoxin translocation, or the movement of a gut bacteria-derived component to the bloodstream, where it provokes inflammation and insulin resistance 3) Inflammation in the fat tissue and intestines 4) The composition of the gut microbes, which are known to contribute to a variety of health factors
The mice fed a high-fat diet supplemented with green tea gained about 20 percent less weight and had lower insulin resistance than mice fed an otherwise identical diet without tea.
Those mice also had less inflammation within fat tissue and the intestine. Furthermore, the green tea appeared to protect against the movement of endotoxin, the toxic bacterial component, out of their guts and into the bloodstream.
Plus, the researchers found evidence of stronger -- less "leaky" -- guts in these mice. Leaky gut is a problem in humans that contributes to widespread low-grade inflammation and has been implicated in a number of health problems.
The researchers also found that the green tea appeared to contribute to a healthier microbial community in the guts of the mice fed a high-fat diet.
Mice fed the normal, or low-fat, diet supplemented with green tea also had benefits including reduced weight gain and lower endotoxin levels and markers of leaky gut.
HOW MUCH TEA?
Green tea consumption in the experiment would be equivalent to about 10 cups of green tea throughout the day for a person, Bruno said.
But even a lesser intake of green tea with meals each day is likely to be of benefit.
Bruno is currently working on a human study that will explore the effects of green tea on leaky gut in people with metabolic syndrome -- a condition that predisposes people to Type 2 diabetes and heart disease.
Eunhee Chung, Salvatore N. Campise, Hayli E. Joiner, Michael D. Tomison, Gurvinder Kaur, Jannette M. Dufour, Lillian Cole, Latha Ramalingam, Naima Moustaid-Moussa, Chwan-Li Shen. Effect of annatto-extracted tocotrienols and green tea polyphenols on glucose homeostasis and skeletal muscle metabolism in obese male mice. The Journal of Nutritional Biochemistry, 2019; 67: 36 DOI: 10.1016/j.jnutbio.2019.01.021
Ohio State University. "Green tea cuts obesity, health risks in mice: Follow-up study in people underway." ScienceDaily. ScienceDaily, 14 March 2019. <www.sciencedaily.com/releases/2019/03/190314075804.htm>. ... See moreSee less
MEDITERRANEAN DIET BOOSTS ENDURANCE EXERCISE WITHIN DAYS, study finds
Researchers at Saint Louis University have found that eating a Mediterranean diet can improve athletes' endurance exercise performance after just four days.
In a study published in the Journal of the American College of Nutrition, investigators found that participants ran a 5K six percent faster after eating a Mediterranean diet than after eating a Western diet.
Researchers found no difference between the two diets in performance in anaerobic exercise tests.
The Mediterranean diet includes whole fruits and vegetables, nuts, olive oil and whole grains, and avoids red and processed meats, dairy, trans and saturated fats and refined sugars.
By comparison, the Western diet is characterized by low intake of fruit, vegetables and unrefined or minimally processed oils and high intakes of trans and saturated fats, dairy, refined sugars, refined and highly processed vegetable oils, sodium and processed foods.
Senior researcher Edward Weiss, Ph.D., professor of nutrition and dietetics at SLU, says the Mediterranean diet is well-established as having numerous health benefits. He and his team hypothesized that the diet's anti-inflammatory and antioxidant effects, more alkaline pH and dietary nitrates might lead to improved exercise performance.
"Many individual nutrients in the Mediterranean diet improve exercise performance immediately or within a few days. Therefore, it makes sense that a whole dietary pattern that includes these nutrients is also quick to improve performance," Weiss said.
"However, these benefits were also quickly lost when switching to the Western diet, highlighting the importance of long-term adherence to the Mediterranean diet."
The study enrolled seven women and four men in a randomized-sequence crossover study. The participants ran five kilometers on a treadmill on two occasions -- once after four days on a Mediterranean diet and on another occasion after four days on a Western diet, with a period of nine to 16 days separating the two tests.
Weiss says the study found the 5K run time was six percent faster after the Mediterranean diet than the Western diet despite similar heart rates and ratings of perceived exertion.
"This study provides evidence that a diet that is known to be good for health is also good for exercise performance," Weiss said. "Like the general population, athletes and other exercise enthusiasts commonly eat unhealthy diets. Now they have an additional incentive to eat healthy."
Michelle E. Baker, Kristen N. DeCesare, Abby Johnson, Kathleen S. Kress, Cynthia L. Inman, Edward P. Weiss. Short-Term Mediterranean Diet Improves Endurance Exercise Performance: A Randomized-Sequence Crossover Trial. Journal of the American College of Nutrition, 2019; 1 DOI: 10.1080/07315724.2019.1568322, and www.sciencedaily.com/releases/2019/03/190306125351.htm... See moreSee less
WORKOUT + WALKING BREAKS = KEEPS BLOOD PRESSURE UNDER CONTROL
High blood pressure, aka Hypertension, affects more than 5 million Australians — no surprise there's an ongoing hunt for methods to prevent and treat the condition.
Such a method is suggested by a new study conducted by a team led by University of Western Australia and Baker Institute researchers.
Their research found that men and women who exercised in the morning lowered their blood pressure, and that women lowered theirs even further by taking brief but frequent breaks from sitting over the rest of the day.
It's well-established exercise lowers blood pressure, while extended periods of sitting have been observed to increase it.
Noting that, the researchers set out to test whether exercise's powers can be enhanced by breaking up those sitting periods.
"This is a relevant question because in the real word, it is possible for a person to get their recommended daily amount of exercise but also to accumulate high volumes of sitting," said the study's lead author, PhD candidate Michael Wheeler.
He and his team recruited 67 men and women aged 55 to 80, who were all overweight or obese, and ran them all through three conditions that each lasted eight hours.
1) In one condition, participants sat without moving the whole time.
2) In a second, they sat for an hour, walked on a treadmill for 30 minutes at a moderate intensity, then sat for the remaining six-and-a-half hours.
3) In the third, they sat for an hour, did their 30 minutes of exercise, but then broke up their sitting with a three-minute light walk every half hour.
Their blood pressure, heart rates and adrenaline levels were measured throughout. The results are published in the American Heart Association journal Hypertension.
LOWER BLOOD PRESSURE
The 30-minute bout of exercise significantly lowered all participants' blood pressure, particularly their systolic blood pressure: that's the first number in a blood pressure reading, which reflects pressure when the heart is beating.
When they just exercised, participants lowered their systolic blood pressure by an average 3.4 points compared to when they just sat. But when they exercised and took breaks from sitting, they lowered it by an average 5.1 points — compare that to medications for high blood pressure, which can lower it by 8-9 points.
REAL WORLD BENEFITS
The study is compelling because it mirrors real-world behaviour — you might go for a jog in the morning, then make a point of taking breaks from your desk job the rest of the day, which could benefit your blood pressure.